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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="Promise.js"></script>
</head>

<body>
    <script>
        let p = new Promise((resolve, reject) => {
            // reject('error');
            // reject('ok');
            resolve('ok');
        })
        p.then(value=>{
            console.log(111);
            return new Promise((resolve,reject)=>{})
        })
        .then(value2=>{
            console.log(2222);
        }).then(value=>{
            console.log(333);
        })
        .catch(e=>{
            console.log('e',e);
        })
        // then方法一般只用来指定成功的回调，使用catch指定失败的回调

    </script>

</body>

</html>